Yieldable barriers



Nov. 25, 1958 E. D. SAWYER YIELDABLE BARRIERS 2 Sheets-Sheet 1 Filed Feb. 27. 1953 :INVENTOR EMERSON D. SAWYER A. D. MKELLAR ATTORNEY Nov. 25, 1958 E. D. SAWYER YIELDABLE BARRIERS 2 Sheets-Sheei 2 FiledTeb. 2'7. 1953 [overs-or? a Shh/ er INVENTOR.

ATTORNEY.

United States Patent YIELDABLE BARRIERS Emerson D. Sawyer, Chicago, Ill.

Application February 27, 1953, Serial No. 339,441

Claims. (Cl. 14-52) My invention relates to certain novel and useful improvements in yieldable barriers, and has as its chief object the provision of a yieldable barrier construction which cannot be the immediate cause of damage to its supporting base, even if the maintenance men neglect to observe the ordinary precaution against wear of the operating cables within the barrier structure and thereby allow the heavy counterweight to drop a considerable distance and strike the bases of the column. Specifically this new improvement concerns more especially the counterweights within the barrier column.

Barriers of the yieldable type must be constructed 'on existent bridges as well as on newly designed bridges which can have specially designed bases. In case these barriers are installed out on the steel trusses of bridges, or on fairly light weight footings sufficiently stable to withstand the superimposed load, as well as the overturning moment due to impact tests, there is the possibility that the sustaining bases of the columns would not be heavy enough to withstand a blow or impact of a falling counterweight. This invention obviates the possibility of any damage to the column bases or supporting structures, such as the shearing of rivets or the cracking of the foundation due to the blow of a falling-counterweight.

Heavy cast iron counterweights are generally necessary in these barrier devices and when the cable supporting these counterweights have become badly rusted or worn, due to the lack of lubrication or chafing, the dropping of a counterweight under such conditions could damage the sustaining base or the sustaining bridge structure very seriously.

Previous to this present improvement of barrier construction, no heavy weight or extra heavy weight barriers had to be built out on fairly light bases. Only the light weight barriers have been built out on steel trusses, and the counterweights of these barriers were fairly light as compared to the counterweights of the heavy and extra heavy type barriers. Hence knowing that these yielding barriers have to be constructed in locations where the sustaining bases are of light weight construction incapable of sustaining a heavy vertical impact blow, this new improved method of barrier counterweight checking device was invented.

The ordinary cushion pads, coil springs :or regular buffer methods are of no avail under these circumstances. Springs are not made heavyenough, and if they were, the recoil produces a rupturing effect, and besides too much space is required for such a buffer and the cost is prohibitive. The abnormal impact and the heat generated by the absorption of this heavy impact within -a few inches poses a problem far out of the ordinary use of conventional buflfers.

Another problem which presents itself is that once this improved buffer device has performed its function, .it can 'be .iesetvready forffut ure use without any general dismantling of complicated parts within the small, very inaccessible space available-for such a buffer device.

the yielding barrier.

2,861,285 Patented Nov. 25, 1958 2 The device must be economical to install, must require practically no attention or maintenance, and must be capable of serving its useful purpose even after lying unserviced for ten years or more.

The cost of the device must be nominal, as this cost must be charged off to supplying safety in the operation of a public safety device.

The invention is not the result of snap judgment, but of a studied engineering investigation. Corrosion, frost, extreme heat, volatility of liquids, and combustion resistance all have to be considered in the devising of this improved yielding barrier counterweight buffer.

The invention consists in the combination hereinafter described and claimed, and will be best understood by reference to the accompanying drawing forming a part of this specification and in which- I Figure l is a front elevational view of my yieldable barrier mounted on a bridge structure.

Figure 2 is a vertical sectional view taken on line 22 of Figure 1 of a barrier column supported on a typical bridge structure, showing the counterweight hanging in balance in the dotted line position with the brake vdrum box of the yielding barrier, anda portion of the newly improved buffer device partly attached to the bottom of the counterweight and partly attached to the base plate of the barrier column.

Fig. 3 is an enlarged detail of the bottom of the counterweight compartment in the barrier column, with the lower portion of the counterweight suspended in its normal, fully lowered position.

Fig. 4 is a section on the line 1-1 of Fig. 3.

Fig. 5 is a detail of the bottom portionof the buffer mechanism in a secondary form.

Referring to Figure 2, a structural frame 1, such as the truss of a bridge, with an attached basesupport 2 on which a barrier column 3 with a base plate 4 is mounted and secured thereto by bolts 5.

Within boX compartment 6 of column ,3 is a drum box 7 in which is mounted on drums 7a payout cables 8, which in turn serve to support the roadway net 8a of Drum box 7 is mounted so as to be moved up .or down in column 3 within the boXcompartrnent 6 by a belt chain 9 sprocket wheels 9a, which is motivated by a geared motor 17 at the bottomofcolumn 3. Emerging from drum box 7 at its top is a supporting cable 10 which passes upward in box compartment 6 over a freely turning sheave 11 at the topof column 3; thence downward in counterweight compartment 12 around the freely turning sheave 13 and up to a becket fastening 14. v

The free turning sheave 13 is mounted to revolve in a sheave frame 15 attached to counterweight 16, shown in solid outline in its normally down position, with the drum box 7 in its normally up position, the Weight of eachbeing in the approximate ratio of 2-to-'1. When the drum box 7 is lowered in the compartment 6 toward the column base 4, then the counterweight 16is moved upward in the compartment 12 and further when the cables 8 are pulled outwardly from within the drum box 7 by the impact of a car on the roadway net; then the counterweight 16 will be raised close to the top of the col umn 3 and well above the base plate 4. Should the top of the counterweight hit the top stopper 8 at such a time and the cable 10 has ben allowed to become worn and weakened due to the lack of lubrication, or years of corrosion, then said cable 10 can be ruptured fairly easily, thus allowing counterweight 16 to drop precipitately with an abnormallyheavy impact force.

No ordinary spring or padded stoppers'or cushions can take 'such a blow without virtually exploding, and then transmitting this blow to the base plate 4 and then into the structural frame 1 through support'z. it; is generally 3 impractical to design bridge frame 1 to take such solid impact, and more especially when the yielding barriers are added to the bridge structure years after the bridge is built. No improvised frame work can be added to take such a solid impact. Therefore, to meet such an emergency condition, this new improved counterweight buffer has been devised which is capable of exerting accumulated shock resistance within the space of a few inches.

1 This is best shown in Fig. 3, to which I now refer. The bottom of counterweight 16 is bored out at hole 19 "to admit plunger bar 20 shrouded in non-corrosive shield -21. Plunger bar 20 is supported partially within counterweight 16 by means of a secured-in-place plug 22 with its inner end fitting into an elongated recess 23 of plunger 20. At the top of plunger 20 is one or more layers 24 "of compressible material'and a lubricating opening 25 is provided to keep the whole of plunger 20 corrosively free on counterweight 16.

Still referring to Fig. 3, near the bottom of plunger 20,

is placed 'an adjustable squeeze collar 26 shown with an adjustable bolt 27 in place in Fig. 4. The lower portion of plunger 20 from where it emerges from counterweight 16 to its lower tip, is very slightly tapered in fact, varying only a couple thousandths of an inch in diameter for the full length of ,the plunger 20, the smaller diameter being '-toward the lower end. The squeeze collar 26 will be preferably made of high quality, non-corrosive steel so -that it can be driven along the plunger 20 with increasing frictional resistance the farther up it is pushed on "plunger 20.

1 The plunger 20 has a blunt taper 40 at its extreme lower end and a very slight taper 39 throughout its full length where it slides within the collar 26. As the tip of the plunger 24) enters the cylinder or tube 31, the globular crushable material 36 wells up around the lower end of the plunger 20 where it enters the tubular cylinder 31.

Two or more layers of compressible material 28 serving zas washers are located below the squeeze collar 26 with a metallic disc 29 holding the compressible material 28 in place on plunger 20 and disc 29 in turn supported by 'short pin 30. An ordinary blow of the counterweight 16 due to the becket fastening 14 slipping a short distance (I on the cable 10, will cause the plunger 20 to enter the top of tube 31, so that the disc 29 bears on the upper rim "of tube 31, thereby forcing the squeeze collar 26 slightly upward along the slightly taperedshank of plunger 20,

- thus developing sulficient resistive friction to take an --'ordinary blow of the counterweight due to its slightly *over-normal travel.

The tube 31 is secured to a base plate 4 at location 32 concentrically in line with the plunger 20 and has an internal diameter considerably larger than the diameter of plunger 20. Openings 33 are provided near the top of tube 31 and drippage opening 34 is provided near the base of tube 31. The inner top edge or top rim of tube 31 is chamfered as at location 35, and the inner pocket of tube 31 is filled approximately three-quarters full to a point 37 with globular crushable material 36, such as graded Ottawa sand.

In case the cable is broken, as described previously, with the counterweight 16 at or near its fully raised position, then the blow due to the dropping counterweight -16, causes the squeeze collar 26 to be pushed upwardly along the plunger with increasing resistance due to the 'islight increase in the diameter of plunger 20. At the same time plunger 20 enters the crushable material 36 and causes this material to first fi-ow upward around the lower 30% of void in the globular condition of this material 36..

The force required to crush this material as well as cause "-it to how past the end of plunger 20 while the squeeze "(collar 26 is at the same time being pushed upward Q11 plunger 20 with increased resistance, all contribute to the resistance required to overcome the abnormal impact caused by the falling counterweight 16.

In replacing the parts after an extreme impact blow, all that is necessary is to reach into compartment 12, near the base of column 3, loosen the bolt 27, and the squeeze collar 26 can be readily tapped down to its low position sustained by the pin 30. If the material 36 within the tube 31 appears to be pulverized, it can be drained out through the opening 34 and fresh material 36 can be poured into the tube 31.

Now referring to Fig. 5, an alternate method of providing crushable material of a viscous nature for use be obtained, such as a blow of steel on steel.

inside of the tube 31 capable of taking the heavy compresheavy impact blow years after the installation of the barrier. The replacing of the container 38 would consistof washing out of the broken particles and crushed material and replacing with a new container 38, which will last indefinitely with its viscous substance contained therein;

It is an established fact that in order to absorb the kinetic energy of a falling object by impact with other objects, the kinetic energy stored up in the moving or falling body must be dissipated in compression, distortion, frictional flow, or finally forceful disintegration in a dust or gaseous state due to the heat or energy of disintegration.

The means used to dissipate the kinetic energy must be commensurate with the impact load of the counterweight to which the plunger is attached. This bumper device is devised for use primarily in connection with a barrier gate of the yielding type having a counterweight of sizeable dimensions and weight, and must serve its purpose only at rare intervals. However, all the component parts shown and called for are necessary to develop the mechanical features of the invention. If thecounterweight drops a short distance, the padding discs or compressibl'e material 24 as well as the compressible material 28, at the lower end of plunger 20, can absorb the impact by simple compression, the force in this case being completely or totally exerted on the top rim of cylinder 31. If the fall of the counterweight is great enough, the

' function of the squeeze collar 26 slidably clamped to the slightly tapered shank ofrplunger 20 oifers its frictional resistance in a varying degree in addition to the above described resistance; and if the downward plunge of the counterweight 17 brings it to its lowered position 16, or lower, the two partial resistance factors aforementioned are supplemented by the forced flow for globular crushable material 36 up'through the space surrounding the plunger 20 within the tube 31; then ultimately for resistance, the globular crushable material 36 is compressed and possibly ruptured in compression, and its air voids finally eliminated as it is reduced to a crushed dust. Hence, with this invention no ultimate solid reaction can Although these varying degrees of resistance can succeed one another practically instantaneously without any appreciable rebound or without fusion, the whole mechanism can be contained in a suitably-small heavy steel cylinder 31 fitted into the base of, or the bottom of the counterweight compartment in the barrier column.

. While I have illustrated and described a precise arrange- 1 therefore do not wish to be limited by the description and drawing forming a part of this specification, but desire to avail myself of such changes as may fall within the spirit and scope of the appended claims.

I claim:

1. In a yieldable barrier gate column having a base portion and a counterweight fitted to move in said column, a buffer device comprising a plunger mounted in the bottom portion of said counterweight having a free end protruding therefrom, a plunger receiving member mounted on said base within said column, and shock absorbing means within said plunger receiving member to absorb impact if the counterweight should fall.

2. In a yieldable barrier gate column having a base portion and a counterweight fitted to move in said column, a buffer device comprising a plunger mounted in the bottom of said counterweight and having a slightly tapered free end protruding therefrom, a squeeze ring frictionally mounted on the lower portion of said free end of said plunger, a plunger receiving member having an open end mounted on said base portion within said column, and said ring having a diameter larger than said open end of said plunger receiving member whereby if said counterweight should fall the plunger will be driven into said plunger receiving member and said squeeze ring will be driven upward on said tapered end of said plunger to absorb impact.

3. In a yieldable barrier gate column having a base portion and a counterweight fitted to move in said column, a buffer device comprising a plunger mounted in the bottom portion of said counterweight and having a free end protruding therefrom, a plunger receiving member mounted on said base portion within said column, and a crushable member within said plunger receiving member whereby if the counterweight should fall the plunger will be driven in the crushable member to absorb impact.

4. The structure of claim 3 wherein said crushable member comprises globular crushable material.

5. A butter device for use in a column having a base portion and a counterweight fitted to move in said column comprising a plunger mounted in the bottom portion of said counterweight and having a slightly tapered free end protruding therefrom, a squeeze ring frictionally mounted on the lower portion of said free end of said plunger, a plunger receiving member having an open end mounted on said base portion within said column said ring having a diameter larger than said open end of said plunger receiving member, and a crushable member within said plunger receiving member whereby if said counterweight should fall the plunger will be driven into said crushable member and the squeeze ring will be driven upward on said tapered end of said plunger to absorb impact.

6. The structure of claim 5 wherein said crushable member comprises globular crushable material.

7. In a yiel'clable barrier gate column having a base portion and a counterweight fitted to move in said column, a butter device comprising a plunger mounted in the bottom portion of said counterweight and having a free end protruding therefrom, a plunger receiving member mounted on said base portion within said column, and a container having crushable material therein within said plunger receiving member whereby if the counterweight should fall the plunger will be driven into said container to absorb the impact.

8. The structure of claim 7 wherein the crushable material within said container is a viscous material.

9. In a yiel'dable barrier gate column having a base portion and a counterweight fitted to move in said column, a buffer device comprising a plunger mounted in the bottom portion of said counterweight and having a slightly tapered free end protruding therefrom, a squeeze ring frictionally mounted on the lower portion of said free end of said plunger, a plunger receiving member having an open end mounted on said base portion within said column, said ring having a diameter larger than said open end of said plunger receiving member and a container having crushable material therein within said plunger receiving member whereby if the counterweight should fall the plunger will be driven into said container and the squeeze ring will be driven upward on said tapered end of said plunger to absorb impact.

10. The structure of claim 9 wherein the crushable material in said container is a viscous material.

References Cited in the file of this patent UNITED STATES PATENTS 1,269,606 Houas June 18, 1918 2,093,612 Lovelace Sept. 21, 1937 2,189,974 Buford Feb. 13, 1940 2,602,249 Sawyer July 8, 1952 

